This invention relates in general to devices for removing a remnant of a pipe, which has been cut off, from a pipe socket in which the pipe had been bonded. As used herein, the term "plastic pipe" shall include ABS pipe, PVC pipe and other plastic pipe.
This invention, although useful for other purposes, was original conceived to address a situation where a remnant of a pipe which was connected to an installed coupling has to be removed. This typically arises when a pipe which is part of a pre-existing structure plumbing has to be replaced. Often the pipe that needs to be replaced couples with at least one other pipe through a pipe coupling, such as a "T" coupling. If the pipe to be replaced is a plastic pipe which had been bonded into a coupling socket, conventional practice has been to cut off the pipe at the lip of the coupling and, through various means, remove the remnant of the pipe remaining in the socket. Heretofore, remnants have been removed by methods of chiseling and scraping, i.e., a hammer and chisel has been commonly used to remove such remnants. However, these methods have proved to be very time consuming and often very damaging to the in-place coupling.
U.S. Pat. No. 3,752,593 by Fitzgerald et al., presents a device for removing plastic pipe remnants from coupling sockets. This device has a plurality of cutters radially disposed around the circumference of a hollow can shaped member containing a spring biased pilot adapted to slide in and out of the can member. The diameter of the pilot and width of the cutters are adapted to a particular socket and pipe size. The spring biased pilot guides the tool, i.e. centers the tool in the pipe remnant during operation.
This invention has many advantages over the prior art including the above-discussed patent because it not only cleans out the remnants of the cut-off pipe, but it also squares up and cleans the coupling socket end face from bonding material remnants. In practice this invention can remove a pipe remnant and clean out a pipe socket in three to five seconds when powered by a conventional drill. Moreover, it is a single integral part considerably less expensive to manufacture than the Fitzgerald et al. device and significantly less prone to malfunctions. The Fitzgerald et al. device is subject to having particles of pipe lodged in the pilot cylinder resulting in restricted or jammed movement of the pilot. Moreover, Fitzgerald et al. device does not have a stop to prevent the cutter from penetrating too far. This invention has a stop means which also functions as a socket end face trimmer.
These advantages and others will be further discussed in the text hereafter or will be readily discernable from a reading of the text hereinafter.